It's also emerged that Cruz had managed to obtain a total of 10 rifles, not just one.

Newly released documents reveal that, in September 2016, an investigator with Florida's Department of Children and Families (DCF) visited the Cruz household after allegations of medical neglect.

The investigator noted Cruz had been diagnosed with depression, ADHD and autism. He also noted that the teen cut both of his arms in a video posted to Snapchat and that he said he planned to buy a gun.

DCF closed the investigation six weeks later, saying the agency found no evidence of mistreatment.

James and Kimberley Snead, who took in Cruz after his mother's death in November, say they had no idea what the 19-year-old was capable of.

In the days since the Valentine's Day shooting, students at Stoneman Douglas High have gone from survivors to activists, calling for stricter gun rules.